Specific Heat

Heat is something, which produces the sensation of hotness or coldness to us. When we rub our hands, they become warm. Warm means hot. In fact, the kinetic energy of the moving hands is converted in the form of heat energy due to the friction between our hands.

According to the kinetic theory of matter, the molecules of the substance have kinetic energy due to their motion. When a substance is heated, its molecule absorbs heat energy and move with higher kinetic energy. Substance having equal masses requires different amount of heat. This specific property of a substance is called specific heat capacity. In this section we will learn more about specific heat.

Specific Heat Capacity

Specific Heat Formula

If someone increase the temperature of the substance, they will be an increase in the kinetic energy of its molecules - that is increase in its internal energy. So one need to supply energy. The energy needed to raise the temperature of an object is proportional to the increase in temperature and mass of the object

$Energy \propto mass \times Temperature\ rise$

Here the constant of proportionality which is depends on the substance, is called the Specific Heat Capacity ($c$).

How To Calculate Specific Heat Capacity

Solved Examples

Question 1: How much energy must
be transferred to raise the temperature of a cup of tea (250 ml) from
293.7 K to 368.8 K. Assume that the tea and water have the same
density(1 g/ml), and specific heat capacity (4.184 J/gK). Solution:

Question 2: The specific heat capacity of water is $4200 Jkg^{-1}K^{-1}$. Calculate
the energy needed to raise a bucket full of water, volume 1.4 litres
from tap temperature, $10^{0}C$ to boiling point.